Absolute measurement of radon 222 activity

Metrological aspects of international intercomparison of passive radon detectors under field conditions in Marie Curie’s tunnel in Lurisia

“…The most critical part of the calibration system is thus the actual activity of the reference radium sources and the diffi culty of extracting the whole radon gas from the bubblers. In order to control these aspects, three methods are followed: 1) the 'absolute method' using radon sealed in glass vial [2]; 2) comparison with reference radon sources of the Czech Metrological Institute (CMI); 3) participation to international intercomparison organized by Consultative Committee for Ionizing Radiation (CCRI) -BIPM. The sources used for 'absolute method' are two glass vial, fl ame sealed, containing about 5 kBq of radon: their activity was determined by  spectrometry measurements (in 4 geometry), with a NaI well detector.…”

Development of a transfer standard for the measurement of low Rn-222 activity concentration in air

“…2 shows the response values of the MWIIC due to the time resolution of 10 min. The certified reference time for the radon activity standard (Picolo, 1996;Dersch, 1998) is marked and is chosen to be t ¼0 for the following measurement. The injection of the activity A is performed at t c ¼ 792 min.…”

Development of a low-level radon reference atmosphere

“…For the realization of the reference atmospheres, there are two different primary methods available at the PTB: 1) the radon-in-air activity standard (Picolo, 1996;Dersch, 1998) and 2) the emanation source.…”